More than one line not deleting from grid

Dear All,

I am using Ax2012R2.

I have one customized form, in that in line level we have one grid, in action pane  there is delete command button, i select multiple lines in line level and trying to delete, but at a time only one line deleting,

Is there any property for this, or we need to manipulate with code, same command button working fine in header level, able to delete multiple lines at a time.